


The Heatwave

by halcyon1993



Series: The Kinky Adventures of a Wolf and His Boy [29]
Category: Teen Wolf (TV)
Genre: Alpha Derek Hale, Alpha/Beta/Omega Dynamics, Anal Fingering, Anal Sex, Animal Ears, Barebacking, Body Worship, Bottom Stiles Stilinski, Breeding, First Time, Knotting, Loss of Virginity, M/M, Making Love, Mating, Mating Cycles/In Heat, Nipple Play, Omega Stiles Stilinski, Oral Sex, Plot What Plot/Porn Without Plot, Post-Coital Cuddling, Rimming, Self-Lubrication, Tails, Top Derek Hale, Werefox Stiles
Language: English
Status: Completed
Published: 2018-09-02
Updated: 2018-09-02
Packaged: 2019-07-06 00:36:51
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 6,563
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15874947
Author URL: https://archiveofourown.org/users/halcyon1993/pseuds/halcyon1993
Summary: The denizens of Beacon Hills are all were-creatures whose heats and ruts take place on the full moon. Omega werefox Stiles has always wanted alpha werewolf Derek Hale to be his, and he won’t go through another moon cycle without him.





	The Heatwave

**Author's Note:**

  * For [Camellia_Hale](https://archiveofourown.org/users/Camellia_Hale/gifts).



Stiles can feel it. It's like an itch he can't scratch because it's living unreachable beneath his skin. The time is almost here, when the moon waxes full in the night sky and everyone disappears into their homes for three days. For some, the lucky ones, it's to have wild heat/rut sex with their mates. For those like Stiles, the ones who have so far been unlucky, it's to grit their teeth and muscle through three days of frustration until their heats and ruts are mercifully over.

But if all goes according to plan, Stiles will be one of the lucky ones this time, when the moon is again full in the sky two nights from now.

"Stiles!"

Looking up from the book he hadn't been reading, Stiles waits until his dad appears in the doorway of his bedroom before responding. "What's up?"

The sheriff sighs. "Your ride's here. Didn't you hear him honking?"

Quickly, Stiles puts his book on his nightstand and gets up from his bed to check himself in the mirror on the inside of his closet door. He is dressed in a pair of tight jeans and a red T-shirt. It's an outfit that is mostly casual—after all, he is only going to the movies with a friend—but he knows the jeans show off his round ass and the V-neck of his T-shirt draws attention his collarbones and the vulnerable pale skin of his throat. All of this is intentional, because he wants the friend he is going to the movies with to be more than a friend. It's all part of the plan he'd spent hours coming up with after last month's heat had ended, when he realised he couldn't stand one more full moon without his chosen mate there to help him through it.

Derek Hale, alpha werewolf.

Derek is six years older than Stiles, but they've been best friends for as long as he can recall. Their families have always lived next to each other, and while Derek had moved a few streets away when he turned eighteen almost six years ago, he and Stiles remained close.

Stiles always knew he wanted Derek. Even when he was too young to really understand his impulses, there was something about the werewolf that drew Stiles to him. He has all but followed Derek around like a kit since he learned to walk by himself, wedging his way into Derek's life and not stopping until he had the werewolf wrapped around his little finger. He probably couldn't have made his intentions more obvious to his parents, especially after he presented as an omega, but they have never called him on it and neither has Derek, although for Derek it's likely just because he can be incredibly obtuse when it comes to matters of the heart.

After double-checking that the orange and white fur on his ears is flat and well-groomed and that his tail is appropriately fluffy, Stiles takes the stairs two at a time. When he reaches the foyer he considers taking a jacket with him. It'll be cold outside, but in the movie theatre it'll probably be warm enough for him to get away without wearing one. He leaves his favourite jacket on its hook next to the front door and just concentrates on quickly slipping on his beat-up white trainers, which haven't actually been white in a long time. He should get a new pair soon.

Stiles exits the house after saying goodbye to his dad and walks as calmly as he can down the front path, toward where Derek has parked his black Camaro on the side of the road.

"Hey, hot stuff," Stiles grins as he climbs into the passenger seat.

Derek rolls his eyes. "Ready to go?"

"Uh-huh."

Once he is strapped in, Derek puts down the parking brake and begins the drive to the theatre. While the alpha's attention is on the road, Stiles watches him and is pleased to discover that he isn't in his usual attire.

Instead of the straight-legged dark-blue jeans and plain tank tops that Derek favours day-to-day, this evening he has chosen to wear a pair of tight black jeans, a heather-grey henley with a snazzy zipper detail at the neckline and a black leather jacket on top. The ears atop his head, which have always been slightly smaller than they should be, are as adorable as ever, and after looking down at where his tail is draped across his lap, Stiles notes that there is not a single black hair out of place, like he'd groomed it just before leaving his house. He looks positively edible, and if Stiles has his way he'll be eating a full-course meal in two nights' time. The fact that Derek has dressed up a bit for him increases his confidence that his plan will succeed.

"So what did you wanna see?" Derek asks him, glancing his way when they reach a red light.

Stiles shrugs. "I dunno. I figured we'd just pick when we're there."

" _The Conjuring_?" Derek suggests. "I thought that looked interesting."

"Maybe."

The rest of the drive is taken in silence. When they reach the theatre and are in line for tickets, Stiles looks up at the listings on the wall behind the counter and decides that, yes, _The Conjuring_ would be a great idea. He can be a living cliché and cuddle up to his 'date' under the pretence of seeking comfort from a scary movie. Without giving his real reasoning away, Stiles tells Derek his choice.

The werewolf nods approvingly. "Sounds good."

When it's their turn, Derek orders the tickets and pays. Before they can walk away to get refreshments, the woman behind the counter, all blue eyes and wavy blonde hair, says, "Enjoy your movie! And I have to tell you, you two make a very cute couple."

Stiles preens, but Derek ruins it. "Oh, we're not together like that," he responds stiltedly, his cheeks slightly pink beneath his beard.

 _Just you wait, Sourwolf,_ Stiles thinks. _Just you wait._

"Oh. Sorry," the woman apologises, looking between them with a frown.

"It's fine," Stiles says, swiftly taking Derek's elbow and dragging him away.

When they finally get to the refreshments, they both get Coke, but Derek only gets sweet popcorn for himself. Stiles goes all out. He gets some popcorn too—with butter, thank you very much—but he also gets some Reese's and a big bag of Skittles. His teeth won't thank him for it later, but he couldn't give less of a damn in the moment. They're just too good to resist.

"Sure you can carry all that?" Derek asks him, one eyebrow raised judgmentally.

Stiles just glares. He picks up his Coke in one hand, carefully pins his popcorn against his chest with that arm and then picks up the Reese's and Skittles with his other hand. "See? I've got it."

"Barely."

"Shut up and lead the way, Sourwolf."

Chuckling, Derek obeys, and a minute later they are in their seats in the very back row of the dimly lit theatre. The other seats are mostly empty, which is good. There will be less talking during the movie.

" _Mmm_ …goddamn, do I love this crap," Stiles moans after biting into a Reese's Cup.

"You're not saving them for the movie?"

"Hell no! They're too good to wait! Here."

Feeling brave, Stiles holds the remaining half of the Reese's Cup up to Derek's mouth, giving him no other choice but to eat it right from his hand.

"I know what Reese's tastes like, Stiles," Derek grumbles. He eats it anyway, and Stiles fights off a shudder when he feels the werewolf's lips against his fingers.

 _Get a grip, Stilinski,_ he chastises himself. _Don't jizz in your jeans already._

The wait for the movie to start passes in comfortable silence. They have only been in their seats for five minutes when the lights dim and the half-hour of trailers begins. Stiles watches the first couple to see if there is anything interesting, but when nothing jumps out at him he stops and focuses his attention on the werewolf sitting next to him. If he turns his head to the left just a little, he can easily see Derek out of the corner of his eye without giving away that he is no longer watching the trailers. The way the colours and flashing lights from the silver screen play across the pretty yet rugged planes of Derek's face is mesmerising, and before Stiles knows it, the movie is beginning.

* * *

When the scares start coming, Stiles goes with his plan and plays up how affected by them he is, jumping dramatically in his seat and holding a hand to his chest.

"You okay?" Derek whispers to him, looking away from the movie.

Stiles bows his head slightly, trying to look demure and tempting. "Y-yeah. Just scarier than I thought it'd be."

"We can leave if you want."

"No, it's fine. I wanna watch it. It's not a bad feeling, being scared like this."

Derek nods and returns his gaze to the movie. Stiles does the same, watching on bated breath as Lili Taylor kneels at the top of the house's basement steps with nothing but a lit match for a light source. When the next jump-scare startles him, his reaction is wholly authentic. He all but leaps out of his seat and some of the popcorn he hasn't eaten yet flies up in the air to land on the row of seats in front of him.

One of the people a few rows further down turns around and shushes him.

"Sorry," Stiles mouths, trying to settle.

"Sure you don't wanna leave?" Derek asks. His lips twitch as he holds back a smile, the sexy bastard.

"Yup."

When he is comfortable again, Stiles releases a deep breath and leans subtly to his left. He can't lean very far without the armrest digging into his ribs, which is annoying, but Derek still seems to pick up on the hint and raises his arm to throw it around his shoulders and bring them as close together as they can possibly be. Stiles _really_ wishes the armrest wasn't there now, because it's all that's stopping him from being pressed flush to Derek's side, which from experience he knows is a wonderful place to be. They don't hug that often—Derek isn't the touchy-feely type, and Stiles respects his boundaries—so Stiles soaks up the attention whenever he gets it. This time is no different.

"Don't worry," Derek murmurs, his breath tickling one of the orange ears sticking out of the hair on Stiles' head. "I'll protect you."

"Such a gallant alpha."

"You know it."

They share a grin, and for the rest of the movie neither of them moves. Stiles is content—and smug, because his plan is going off without a hitch.

* * *

Just over an hour later, Stiles gets out of Derek's car on the street in front of his house. There are no lights on in the windows, so his dad is presumably asleep. Good.

Derek gets out of the Camaro too and walks him up to the door. It really is like a date.

"So…" the alpha says awkwardly when they stand facing each other on the porch.

"So."

"I had fun tonight."

"Me too."

Now that the moment is here, Stiles finds it difficult to get out the most important question he has ever asked anyone, but when he looks up into Derek's hazel eyes, something about the emotion in them gives him confidence.

"I wanted to ask you something," he says, scratching the back of his neck.

Derek takes a small step closer, hands in the pockets of his leather jacket. "Yeah?"

"You don't have someone to spend your next rut with, do you?"

Derek blinks and slowly shakes his head. "No."

"Cool. Me neither. With my heat, I mean."

"Oh."

Stiles chuckles nervously. Wow, this is harder than he thought it would be. "Do you…"

"Do I?" Derek prompts after a couple seconds.

"Do you maybe wanna…spend them together this time?"

 _And maybe all the times after, until we're both old and grey,_ Stiles adds in his mind.

"Like…friends with benefits?"

Stiles' response is a vehement, " _No_." He would prefer nothing to that.

Derek takes another step, the emotion in his eyes more prominent now. "Like mates then?"

Stiles nods.

"How long've you wanted that?" Derek enquires, so close now that all Stiles can smell is his aftershave, the leather of his jacket and his wonderful alpha musk beneath that.

"Since forever," Stiles replies honestly, putting it all out there. "I've never wanted anyone else."

Derek holds the omega's eyes for several agonising seconds, appraising him, searching for something in his face. Finally, he must see it. "I'd love to."

Hardly daring to believe his ears, Stiles becomes wide-eyed. "Really?"

The werewolf takes his hands out of his pockets, wraps his arm around the small of Stiles' back and drags their middles together, leaving no space between them. "Really," he confirms.

"Kiss me."

Derek's lips are just as soft as Stiles has always imagined them to be. The kiss isn't much to write home about, at least it probably wouldn't seem like it for an onlooker. Part of Stiles wants more, to part his lips and welcome Derek's tongue inside his mouth, to lose himself completely in the alpha until there is no part of him that belongs just to himself. He wants to belong to Derek entirely, but for that he will have to wait another two days for the full moon. For now, Stiles sinks into the kiss as it is, closed-mouthed and tender, the bristles on Derek's cheeks scraping across his own smooth ones. Even so simple, the kiss is still perfect in every way.

When it ends, Derek rests their foreheads together and cups Stiles' face, thumbs stroking across the elegant slopes of his cheekbones. "Come over in the evening?" he asks.

Stiles hums, unable to wipe the sappy smile from his lips. "Okay."

With much reluctance they bid each other goodnight. Before he goes inside the house, Stiles watches Derek walk back toward his car and his heart flutters in his chest when he sees how Derek's tail wags enthusiastically behind him.

When the sound of the Camaro has faded, Stiles unlocks the front door, steps inside and leans back against it once it's closed.

Mission accomplished.

* * *

In the few minutes he has left before Stiles is due to arrive at his house, Derek bustles about in a bit of a panic. He has to make sure he has got everything prepared for their first time together, and for Stiles' first time in general. He has to be the best alpha he can be, to take care of Stiles, which means having the necessary items to last them three full days—food; water; lube; plenty of knot-safe condoms, if Stiles wants him to wear them.

It's a lot.

He has taken his role as the alpha very seriously the few times he has welcomed someone into his bed in the past, but never has it been this important. Those previous times were like favours to people he was distant enough from that it wouldn't become weird afterward. There were never any romantic feelings involved, but he did everything in his power to make sure those ephemeral partners left completely satisfied after the last day. With Stiles it's going to be so different, because his heart has belonged to the omega werefox for the longest time.

Derek had never done anything about his feelings before because he'd wanted to wait. The age difference between them had always meant he had more responsibility, and he had never wanted to put any pressure on Stiles to progress their friendship into something more before Stiles was ready. He waited patiently for the omega to make the first move, and when Stiles suggested going to the movies two days ago and the evening very swiftly ended up feeling like a date, he'd been so excited. He didn't let it show at first, but then, when they were on Stiles' doorstep and Stiles finally asked for them to be more…it was the happiest Derek ever remembers being.

That's why it's so important that this full moon cycle goes well. Messing it up would kill him.

His ears twitch atop his head when his doorbell rings. It's time.

"Okay…you've got this," he tells himself. He smooths his hands down the thighs of his jeans before walking to the front door and opening it.

Stiles stands on the doormat looking just as nervous and excited as Derek feels. He wears an off-white T-shirt and a pair of pale-orange shorts.

"Hey," Stiles says, waving like a dork. Derek's dork.

"Hey," the werewolf echoes, stepping aside to let him enter the house.

"You ready for this?"

"Yeah, I think I've got everything good to go." Derek begins listing off the preparations he has made, but Stiles stops him by pressing a finger to his lips.

"Relax, Sourwolf," the omega says softly. "I trust you."

Those three simple words are all it takes for Derek to calm down. He has done this before and never had any issues, so he'll manage just fine this time. And even if an issue unexpectedly crops up, they'll handle it together.

"God, I hate this feeling," Stiles complains, shaking himself.

Derek knows what he means without having to ask. He feels it too, the same itch that has been getting worse over the past few days. The good thing is it will relieved soon.

"C'mon," he says, taking Stiles' hand and leading him into the bedroom. "I figured we could watch TV in here or something until it's time."

"Good plan."

For the next couple hours, Derek sits through two episodes of _Game of Thrones_ while the sun sets behind the pale-grey curtains obscuring his bedroom window. Stiles has just put on a third episode when it happens, when the uncomfortable feeling beneath Derek's skin turns into a raging conflagration, all the blood in his body shooting down to his cock. He looks at Stiles sitting next to him and sees that the omega's cheeks are flushed and his eyes are already slightly hazy.

"G-guess it's time," Stiles stammers, tugging at the neck of his T-shirt.

"Yeah."

Derek checks for what must be the tenth time that all the necessary supplies are in place on his nightstand and then gets up on his knees. As the omega, Stiles' devolvement into incoherency will be more rapid than Derek's, so Derek makes quick work of helping him out of his shirt and then to lie down. He is momentarily distracted by the pale, mole-dotted skin of Stiles' torso. It's nothing he hasn't seen before, of course, but it's beautiful and now Derek can actually let himself look. He spends a few seconds doing just that, skating his fingertips over Stiles' flat but soft stomach, dipping briefly into his navel, before he resumes disrobing him.

Next to go are Stiles' shorts. Derek undoes the button, pulls down the zipper and meets the omega's hooded eyes before he pulls them down.

"You're still one hundred percent sure you want me as your mate, right?" he asks him.

Stiles huffs. "Ask me that again and I'll scratch your eyes out, and that would be a shame, 'cause they're very pretty eyes."

Derek chuckles and is reassured. "Yes, sir."

When the shorts are off and join Stiles' shirt on the floor, Derek is stunned to discover that the omega isn't wearing any underwear. He is completely bared to him, and Derek is unable to close his mouth as he stares openly between Stiles' legs. His omega cock is much smaller than Derek's, and his balls are purely decorative, but Derek believes he is perfect.

"Beautiful…" he murmurs, stroking his hands up the insides of Stiles' thighs.

"You too," Stiles whines. "Wanna see you too."

"Okay."

Derek moves off to the side of the bed and stands facing his soon-to-be mate—isn't that a heady thought?—as he gets naked. His henley is the first thing to go, and he proudly puffs out his hairy chest when he hears Stiles' sharp inhale.

"Like what you see?" he asks.

Stiles nods jerkily and makes grabby hands at him.

"Just a minute," Derek says, undoing his jeans and pushing them down his muscular legs. He takes care of his socks while he is down there and kicks out of his black boxer-briefs before rejoining Stiles on the bed. He doesn't allow the omega a chance to sit up. Instead he takes his place between Stiles' legs and puts some of his weight atop him, their torsos pressed together as he kisses him. It's a much different kiss than the one they'd shared at the end of what Derek supposes now was their first proper date. This one is full of passion. He licks across the seam of Stiles' lips, seeking entrance which he takes as soon as it is granted to him. When the first taste of the omega hits him, he moans and starts rolling his hips, rubbing their erections between them.

"Derek!" Stiles gasps against his mouth, making him smirk.

"Feel good?" Derek responds smugly.

"Y-yeah. Want more…"

"Soon, baby."

The pet name makes Stiles' eyelids flutter and intensifies the colour in his face. Derek takes note of this as he begins his descent down the omega's body, pressing kisses and sucking marks as he goes.

Starting with his neck, Derek is pleased to see that Stiles' pale skin marks up so easily, so prettily. He nibbles on the vulnerable flesh and is touched by the trust Stiles displays when he tips his head back and bares his neck entirely. It puts him at Derek's mercy, and the wrong sort would take advantage of this trust, use it to hurt him, possibly even kill him. The thought is anathema to Derek, and he growls softly as he sucks on Stiles' Adam's apple, making Stiles shake beneath him. Casting such stupid thoughts aside—the omega is his, after all, and no one will get close enough to hurt him under his watch—Derek just focuses on the here and now.

He has never been the most demonstrative of people, something which his Uncle Peter and his older sister Laura have always loved to tease him for. Words just don't come naturally to him, so instead of trying and making a fool out of himself, he usually prefers to use actions. That's what he does now, lavishing Stiles with as much pleasure and affection as he can muster.

Derek continues downward, nipping at Stiles' right collarbone before he reaches his pebbled nipple. Taking it in his mouth, he sucks on it hard and smiles around it when Stiles moans and tangles his long fingers in his hair. He keeps going until the nub is red and abused-looking, then he relents, purses his lips and blows a breath across it, the saliva he left behind no doubt making it feel cold. Sure enough, a shudder racks through Stiles' body, and Derek only stops blowing air when Stiles whines plaintively. He doesn't go easy on him though, instead switching to his other nipple to repeat the process all over again. Only once they're both in the same over-sensitised state does Derek move on.

Even further down, he dips his tongue into Stiles' bellybutton and then shoves his nose into the brown curls at the base of his cute little cock. He breathes in the musk of his sex and moans when it goes straight to his head. He can pick up the scent of slick as well, which nearly makes him drool. Before he can start, he picks up Stiles' cock from where it is curved hard against his pubic bone and sucks him into his mouth. At just four and a half inches long, it's easy for Derek to take him all the way. He puts his all into it, making Stiles' first blowjob one to remember.

He fondles Stiles' smooth balls with one hand and presses the other to Stiles' stomach, holding him down so that he can take full control.

"Derek…please," the omega whimpers, his hips twitching. "Need you…"

Sucking one last time, Derek pulls off of Stiles' cock and savours the taste of his skin and the salt of his pre-come. "Impatient, huh?"

"Can't help it," Stiles responds, his hands fisted in the sheets on either side of his hips. "It's kinda starting to hurt."

This worries Derek. He'd thought they had more time, but evidently Stiles' heat is hitting him hard and fast. He scraps the plans he'd made to ease into things slowly, to worship every inch of Stiles' body with his mouth. They will have plenty of time for that later.

"Okay," he says, tapping Stiles' hip. "Turn over. I'll take care of you."

"Thank God…"

Stiles does as he has been told and raises his tail so that it is draped up the length of his back, giving Derek a fantastic view of his ass. Each cheek is pale and smooth. Derek presses a kiss to both of them before taking them in his hands and pulling them apart to reveal Stiles' tight virginal asshole. It glistens with slick, and as he looks for a few seconds a thin trail of the translucent fluid dribbles down Stiles' perineum to his balls. He only stops looking when Stiles mewls and arches his back, pushing back into Derek's hands.

"Shh, I've got you," Derek whispers. He needs to taste, so he does.

Leaning down, Derek swipes his tongue in a long line from Stiles' balls all the way up to his hole. His cock drips pre-come between his legs and his tail wags lazily when the sweet taste of Stiles' slick bursts across his taste buds. It's like salted caramel with a hint of cinnamon, an unusual combination but one Derek immediately enjoys. He goes back for more, swirling his tongue in circles around Stiles' reflexively clenching hole to get his slick right from the source. It's warm and goes down his throat easily, and already he knows he is addicted to the taste. He has sampled the slick of omegas before, but not one of those times compares to now. There's just something _extra_ about Stiles, some unique quality to his slick that makes it taste a hundred times better.

For a stretch of time that is probably too long, Derek stays with his face between Stiles' cheeks and eats him out. It isn't until Stiles releases a choked sound like a sob that he remembers what he is supposed to be doing.

"Sorry…got carried away," he mumbles, sliding his index finger inside the omega.

"Need your cock," Stiles whines into the pillow around which his arms are wrapped, holding onto it so tightly that Derek wouldn't be surprised if it were to explode.

"You'll get it soon, baby."

There's that reaction again, goosebumps raising on Stiles' skin. _Gorgeous,_ Derek opines in his head. _And so responsive._

Over the next few minutes the alpha works his fingers into Stiles' hole. He thrusts his index in and out a few times to allow Stiles to get used to it, then he adds his middle in alongside it and scissors them gently apart, spreading the omega open. He looks down the length of his own body and gives his aching cock a couple of strokes with his free hand, certain that, even with a lot of prep work, it will be a lot for Stiles to take, especially given that it's his first time. At nine inches long, Derek is definitely well-endowed, even for an alpha. His cock is thick and heavy in his hand, pre-come continuously dripping from the slit now that he has the aftertaste of Stiles' slick on his tongue and the heat of his body around his fingers.

Derek inserts a third finger into Stiles' hole and is amazed by how tight he still is. He can't wait to feel what it's like around his cock. The base of his erection already throbs so hard it's almost painful and his skin glistens with sweat, his bedroom already reeking of the combined scent of them as the pull of the full moon outside brings out the beginnings of his rut.

His inner wolf is desperate to get inside of Stiles, to bring them both the relief they need and even breed him up with his pups. It's a startling thought because Stiles is only seventeen. He is only a month away from turning eighteen, but still. It seems too young for pups or kits, but Derek decides it's not something he should worry about just yet. After all, he bought the condoms for a reason.

"That's enough," Stiles rasps once Derek has worked in his pinky finger.

"You sure?" the alpha asks.

Stiles glares at him over his shoulder, his forehead beaded with sweat. "Just get inside me already!" he orders. "You're taking too long."

Derek huffs. "Well excuse me for not wanting to hurt you."

Stiles' glare softens a bit. "I appreciate that, but the longer you wait, the more my insides are cramping up and they won't stop until your knot is in me. So…please."

With a nod, Derek extracts his fingers and wipes them off on the bedding. "Do you want me to use a condom?"

"Huh?"

"A condom, so you don't get pregnant yet. Do you want me to wear one?"

"Have you gotten tested recently?"

Derek nods. "I was all clear the last time and I haven't been with anyone else since."

Stiles purses his lips and his tail swishes from side to side across his back as he thinks. "No condom," he decides eventually.

"Are you sure? You're still only seventeen," Derek points out.

"And if you end up knocking me up, I'll be like, the twentieth omega to get pregnant in my grade. Hell, there were about five whose alphas knocked them up in freshman year. We'll handle it. Besides, the thought of carrying your pups is kinda…nice."

Derek smiles at the pretty blush that appears on Stiles' face with this admittance. "Alright then."

Forgoing the condoms, Derek retrieves the lube from his nightstand and uses it to slick himself up. That done, he gets into position, draping himself over Stiles' back. He holds himself up with one arm to the left of Stile's head and aims the tip of his cock at the omega's hole with his other hand. "Ready?"

"Yeah," comes Stiles' breathy reply.

The first push in is difficult. Even with the prep Derek had done, Stiles is incredibly tight, almost refusing to allow Derek entrance. But the alpha persists and eventually the omega's hole opens up and the head pops inside. Both of them moan loudly and Derek's arm almost gives out from how good it feels. He just about manages to keep holding himself up, not wanting to crush his mate-to-be beneath the substantial weight of his muscular body. He keeps going, feeding Stiles his cock inch by inch until his hips are flush to Stiles' smooth ass cheeks and his big, low-hanging alpha balls rest above Stiles' much smaller ones.

"Okay?" Derek enquires, feeling how tense the omega is beneath him.

"Y-yeah…just gimme a minute," Stiles requests. "You're damn huge, dude."

It's one of the hardest tasks Derek has been given. The alpha in him wants to let loose, to fuck into Stiles' body with abandon, without a care for the omega himself, just simply chasing his own pleasure and release. But Derek would never do that. He is stronger than that, isn't some base animal, even in the throes of his rut, so he holds his inner wolf back until Stiles gives him the all-clear, and even then he moves slowly, withdrawing his cock until just the head remains inside before he slides back in.

With each slow, unerring thrust, the glide gets easier as Stiles' no-longer-virginal hole gets used to being filled up. Only then does Derek begin to move a bit faster.

After a minute, Stiles moves with him, pushing his ass back in time with Derek's syrupy thrusts to get him just a bit deeper. Stiles has his hands fisted in the sheets again and small whimpers and whines slip from his parted lips every time Derek sinks in all the way. Derek has never heard sexier sounds, and he can't believe that he lasted as long as he did without experiencing this.

"Faster!" Stiles gasps eventually, shoving himself back hard against Derek.

The werewolf complies. He rearranges them slightly so that he is straddling Stiles' thighs and his front is pressed to Stiles' back, his muscular arms wrapped around him. This puts more of his weight on the omega, but Stiles doesn't seem to mind at all. If anything, the werefox just moans louder and turns his head to capture Derek's mouth in a filthy kiss. It's uncoordinated as hell, teeth clacking together and spit getting everywhere, but Derek wouldn't change a thing about it. It's the best kiss he has ever received, already eclipsing the one he'd shared with Stiles after their movie date.

It doesn't take long for Derek to feel the base of his cock expanding as his knot forms. It gets progressively harder to push all the way inside, and every time he does a choked sound is forced from Stiles' lips, like he is being punched in the stomach.

For a moment Derek is concerned that he is causing his omega pain, but then he registers that Stiles is still moving with him, at least as best he can while pinned beneath him. Sweat makes their skin slide together, makes it easy for Derek to slide one of his hands between Stiles' front and the bedsheets until he can grasp his small omega cock and stroke him in time with his thrusts. After just three strokes Stiles goes off like a firework, clenching tight around Derek and coating his hand with thin, useless semen.

The scent of it and the unremitting tightness of Stiles' hole is what sets Derek off too. He sinks in to the hilt one final time and then stays there as his knot expands all the way, locking them together as he shoots deep up in Stiles' guts, painting his insides and likely impregnating him with his pups. The thought is so hot, of Stiles' belly all round and swollen with a whole litter, that Derek is no longer able to suppress his instincts. He grinds his hips against Stiles' ass to sink his knot even deeper inside his body and feels the shift come over him, his teeth lengthening into sharp fangs that he uses to break the skin between Stiles' shoulder and neck.

His eyes clenched shut and his wolf ears laying flat atop his head as his balls continue emptying, Derek holds on to his omega for dear life as he is overcome by the connection blossoming between them, the thread he can feel and visualise in his mind that runs from the alpha wolf inside him to the omega fox inside Stiles. It's such an intimate feeling. Derek has heard stories, has seen the mating bond in action between his own parents, between his older sister and her mate, but nothing could have prepared him for how right it is, how much it completes him, gives him everything he hadn't known he'd even been missing.

After extracting his fangs, Derek licks the blood from his lips and then licks over the wound he left on Stiles' neck. The omega shakes beneath him.

He rolls them onto their sides and murmurs, "Doing okay?"

Stiles whimpers and snuggles back into Derek's reassuring hold. "Yeah…it's just…"

Derek understands what he means without him having to finish his thought. "I know."

"Wow."

"Mmhmm."

"We're mated. Your my alpha."

"I am. And you're my omega."

Stiles wiggles a bit then and makes a contemplative sound. "I've never been knotted before."

Derek hums. "How's it feel?"

"It feels…like I've finally got what I was missing this whole time. Does that sound dumb?"

"Not at all." Derek holds Stiles tighter. "I feel the same way."

Both of them are content to just lie there for as long as it takes for Derek's knot to go down. Derek spends the time getting used to the second presence in his chest, to the giddiness his wolf feels because he has finally claimed Stiles. In his mind's eye, he pictures his wolf gambolling with Stiles' fox, the animals playing with each other and rolling around in a forest. It's amazing.

In the end it takes just over half an hour for his knot to deflate, and then Derek slips out of Stiles' body. A gush of thick seed and slick follows, practically drenching the bedding, but Derek will take care of that later. For now, he helps Stiles up off of the bed and into his bathroom to wash their mating from their bodies. Part of him doesn't want to do it because he wants his scent to remain on his omega for as long as possible, ensuring that there is no doubt as to who he belongs to, but Derek consoles his inner wolf with the promise that they'll just do it all over again later. They've still got just over two days of heat/rut sex to get through, after all.

Once fresh sheets have been put on the bed, Derek lies down on his back and Stiles cuddles up to his side, head on his shoulder and fingers playing with the dark hair on his chest. He drapes his red-and-white tail over Derek's thigh, where he twines it with the alpha's black one.

"What happens now?" Stiles asks sleepily.

"Now we nap."

"And then?"

"We make love again when the next wave hits."

"And then?"

Derek chuckles. "Are you going to stay living with your dad?"

Stiles shrugs. "I dunno. We didn't really get around to discussing it when I told him I was spending the full moon with you."

Derek is quiet for a minute, gathering his nerve. When he has it, he asks, "Do you want to live here?"

Picking his head up, Stiles stares down at Derek with a small frown. "I'd love to, but I'd need my dad's permission 'cause, y'know, still technically underage here."

"Only for another month."

"Well, if he says no, we can just wait 'til then, can't we?"

"And the possibility of pregnancy?"

Stiles moves his hand from Derek's hairy chest to stroke over his own flat stomach. "I hope I am."

"Your dad's going to have something to say about that too."

"We're mates now. He can't do anything about it."

"I guess."

"Whatever, I'm tried and all this can wait. Sleepy time now."

"Sure."

With a fond smile, Derek wraps his arm back around Stiles and nuzzles the top of his head. His brown hair tickles his nostrils, but he doesn't move. He falls asleep quickly, wholly content to have his new mate warm and safe in his arms.

**Author's Note:**

> I'd like to say a huge thank you to Camellia_Hale for giving me this prompt. I hope you found this result more satisfying than the result of our previous collaboration. :) I made a conscious decision to put less focus on describing Derek's body this time around, as I'd done that almost to excess with the past few PWPs I'd written and I figured it was Stiles' turn. But, for anyone who missed my usual poetic waxing about Derek's physique, I'll just tell you to watch out for the PWP I'll be writing next... ;)
> 
> Stay tuned for my next prompt fill, this time for Wescottwomen, in which Stiles, an alpha, transfers to a new high school and is instantly enamoured with one of his teachers, the omega Mr. Hale.
> 
> **P.S. Don't forget to subscribe to me to be notified when my future fics go live, which will all be Sterek. And please check out my past fics if you haven't already and are interested.**


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